(Above - a Google maps screen shot of a typical I-75 ramp near Wesley Chapel, FL.)
Observation #7:
I'm back in Ontario now, and had this realization...
Interstate on-ramps in the southern states I passed through are quite short. They're expecially short considering the speed limit on the connecting freeway might be 70 MPH / 113 km/h. (So traffic may be going 75+ MPH / 121 km/h)
On some of these ramps, it would be a real challenge to get up to speed and "zipper merge" into the flow traffic in a relatively low-powered and/or heavy vehicle.
I think I now understand why some people/car reviewers are nervous about cars like the Mitsubishi Mirage (74 hp 2014-2015; 78 hp 2017+). On some of these short ramps, you would literally have to accelerate flat out, foot to the floor, to get up to freeway speed by the merge point. Add a headwind and/or an incline and it gets even more challenging.
Ontario has very generous on-ramps by comparison, probably designed so that big trucks have enough room/time to merge at the speed of traffic. As a result, I've
never felt uncomfortable driving low-powered cars around here.